Damping device

ABSTRACT

A damping device, in particular for damping or avoiding pressure surges, such as pulses, in hydraulic supply circuits, preferably in the form of a silencer, having a damping housing which surrounds a damping chamber and has at least one fluid inlet ( 3 ) and at least one fluid outlet ( 5 ) and a fluid receiving chamber ( 7 ) which extends between the fluid inlet and the fluid outlet, wherein, during operation of the device, a fluid flow crosses the damping chamber in a throughflow direction ( 11 ), coming from the fluid inlet ( 3 ) in the direction of the fluid outlet ( 5 ), and wherein at least parts of the fluid receiving chamber ( 7 ) extend in at least one extent direction transversely with respect to the throughflow direction ( 11 ), is characterized in that the fluid receiving chamber immediately adjoins the fluid inlet ( 3 ) and the fluid outlet ( 5 ) and in that a guide element ( 51 ) is provided in the damping chamber, the fluid flow being able to flow against the guide element and the guide element changing the flow speed of the flow at least in sections.

The invention relates to a damping device, in particular for damping oravoiding pressure surges, such as pulsations, in hydraulic supplycircuits, preferably in the form of a silencer, having a damping housingwhich surrounds a damping chamber and has at least one fluid inlet andat least one fluid outlet and a fluid receiving chamber which extendsbetween the fluid inlet and the fluid outlet, wherein, during operationof the device, a fluid flow crosses the damping chamber in a throughflowdirection, coming from the fluid inlet in the direction of the fluidoutlet, and wherein at least parts of the fluid receiving chamber extendin at least one extension direction transversely with respect to thethroughflow direction.

Damping devices of this kind are state of the art. Such hydraulicdampers, which are also referred to as sound dampers or silencers, serveto reduce oscillations, which are generated by pressure pulsations, towhich a corresponding hydraulic system is repeatedly subjected, inparticular due to the operation of hydraulic pumps. As is disclosed inthe document DE 102 17 080 C1, the known damping devices of this kindhave a damping housing in the form of a circular cylinder, which isrounded in a spherical manner at both axial end regions, with the fluidinlet and the fluid outlet being located coaxial to the cylinder axis ona respective end region. As the damping chamber, which the fluid flowcrosses from the fluid inlet to the fluid outlet, a damping tube isprovided in such damping devices, which extends coaxially between thefluid inlet and the fluid outlet and which, in the tube wall, hasopenings to the fluid chamber surrounding the tube. According to thecylinder diameter, the fluid chamber is radially expanded relative tothe axial throughflow direction defined by the damping tube.

On the basis of this prior art, the problem addressed by the inventionis to provide a damping device of the type considered, which, whilehaving a simple construction, is distinguished by an advantageousoperational behavior.

According to the invention, this problem is solved by means of a dampingdevice having the features of claim 1 in its entirety.

According to the characterizing part of claim 1, a significantdistinguishing feature of the invention is that the fluid receivingchamber immediately adjoins the fluid inlet and the fluid outlet and inthat a guide element is provided in the damping chamber, onto whichguide element the fluid flow can flow and which changes the flow speedof the flow in regions. Thanks to the direct connection of the fluidreceiving chamber to the fluid inlet or fluid outlet and the resultingomission of a damping tube, the device according to the invention isfirstly distinguished by a simplified construction. In damping devicesof this kind with a fluid receiving chamber extending transverselyrelative to the throughflow direction, the so-called disk silencers, theflow speed behavior inside the fluid receiving chamber has a significantinfluence on the damping performance. The guide element onto which fluidcan flow that is provided according to the invention makes it possibleto partially accelerate the flow so that, by contrast with a freethroughflow from the fluid inlet to the fluid outlet, a flow speedfavoring damping efficiency can be achieved, including in the sideregions of the fluid receiving chamber. Installation parts serving asthe guide element can have any geometrical shape whatsoever, whichproduce a partial acceleration of the flow without an excessive increasein the flow resistance.

In particularly advantageous exemplary embodiments, the fluid receivingchamber is formed by a cavity in the form of a disk with two boundarywalls which extend parallel to one another and determine the thicknessof the disk, with the guide element extending in a continuous mannerfrom one boundary wall to the other boundary wall. The disk-like cavitycan advantageously be formed cylindrical or as a polygon or can have anyother shape differing from the circular shape.

The arrangement can particularly advantageously be such that parts ofthe fluid inlet and of the fluid outlet extend in alignment with theboundary walls in the damping housing. In such an arrangement, the fluidinlet and fluid outlet formed as damping housing bores can have anidentical diameter and said diameter can correspond to the spacingbetween the two boundary walls.

The guide element can particularly advantageously be arranged in aposition aligned with the housing axis extending from the fluid inlet tothe fluid outlet, with the guide element preferably being arranged atleast approximately in the region of half of the length of the housingaxis which extends from the fluid inlet to the fluid outlet.

In particularly advantageous exemplary embodiments, the guide element isformed as a flow divider with guide surfaces which extend to both sidesfrom a narrow onflow region which faces the fluid inlet and which islocated on the housing axis. This makes it possible to realize flowspeeds that are favorable to the damping effect even in the outerregions of the disk-like cavity which are distanced from thelongitudinal axis.

The damping housing can particularly advantageously be formed in severalpieces,

-   -   with a pot-like base part, which receives a disk-like central        recess forming part of the cavity with the one boundary wall and        also the fluid inlet and the fluid outlet, and    -   with a flange-like cover part which, with the other boundary        wall as part of an engagement piece, engages in a flush manner        in the central recess when the cover part is fixed to the base        part.

The guide element is preferably formed integral with the cover part insuch a way that it projects from the boundary wall formed on theengagement piece.

For the purpose of sealing the cavity relative to the environment, asealing device can be arranged on the engagement piece of the coverpart, which sealing device is in particular in the form of a sealingring inserted in a circumferential groove, which forms a seal at thecentral recess of the pot-like base part.

For a pressure-tight formation of the damping housing, the cover partcan have, lying opposite diametrical to its vertical axis, severalpenetration bores which, penetrated by fixing screws, fix the cover partto the base part. The arrangement can advantageously be such that thefixing screws, while leaving the region of the fluid inlet and the fluidoutlet free, are arranged uniformly along an external circumference onthe damping housing, which surrounds the disk-like fluid receivingchamber. The damping housing can thus be designed for reliable operationat a high pressure level, for example in the range of 200 bar.

For the connection to a corresponding hydraulic system, a receptaclefora sealing ring can be provided at the fluid inlet and/or at the fluidoutlet in the damping housing, which sealing ring surrounds the fluidinlet and/or the fluid outlet. In the manner of a fixing block, thedamping housing can be fixed to third components by means of severalfixing bolts, which surround the region of the fluid inlet and/or of thefluid outlet.

The invention is explained in detail below with reference to anexemplary embodiment depicted in the drawings, in which:

FIG. 1 shows a simplified sketch-type depiction of the main course ofthe fluid flow in the fluid receiving chamber of a damping device in theform of a disk silencer;

FIG. 2 shows a depiction corresponding to FIG. 1 in a damping deviceaccording to the invention;

FIG. 3 shows a perspective oblique view, depicted at approximately halfthe size of a practical embodiment, of an exemplary embodiment of thedamping device according to the invention;

FIG. 4 shows a top view of the exemplary embodiment of the dampingdevice;

FIG. 5 shows a longitudinal section of the exemplary embodiment alongthe cut line V-V of FIG. 4;

FIG. 6 shows a partial view of only the fluid outlet-comprisingconnection region of the damping housing of the exemplary embodiment;

FIG. 7 shows a partial view, corresponding to FIG. 6, of the fluidinlet-comprising connection region;

FIG. 8 shows a side view of the cover part of the damping housing of theexemplary embodiment;

FIG. 9 shows a top view of the cover part;

FIG. 10 shows a sectional depiction of the cover part along the cut lineX-X of FIG. 9, and

FIG. 11 shows a perspective oblique view of the cover part, seen on thebottom side thereof.

With reference to the attached drawings, the invention is explained onthe basis of the example of a so-called disk silencer, the basicconstruction of which corresponds to subsequently published prior art,as is described in the patent application DE 10 2014 005 822.0. Insidethe damping housing of such a silencer, which damping housing is sealedin a tight manner relative to the environment except for a fluid inlet 3and a fluid outlet 5, said silencer has as a damping chamber a fluidreceiving chamber immediately adjoining the fluid inlet 3 and the fluidoutlet 5, which is formed by a cavity 7 in the form of a flat circulardisk, with only the circular contour thereof being shown and identifiedwith the reference numeral 9 in the simplified, sketch-type depictionsof FIGS. 1 and 2. As can be seen, the fluid inlet 3 and the fluid outlet5 are diametrically opposite one another, with the housing axis 11 whichextends between the fluid inlet 3 and the fluid outlet 5 correspondingto the throughflow direction of the fluid flow.

As can be seen most clearly from FIGS. 3 and 5, the damping housing isformed from two main parts, namely, a base part 13 and a cover part 15.In order to form the disk-shaped cavity 7, the base part 13 has acentral recess 17 in the form of a pot, the flat base surface of whichforms the bottom boundary wall 19 of the disk-like cavity 7. The topboundary wall 21 determining the thickness of the disk, which extends ina parallel plane to the bottom boundary wall 19, is located at thebottom side of the cover part 15. The fluid inlet 3 and the fluid outlet5 are aligned with the boundary walls 19 and 21, so that the diameter ofthe inlet 3 and the outlet 5 respectively corresponds to the diskthickness of the cavity 7. At the fluid inlet 3 and at the fluid outlet5, the base part 13 has a respective flattening 23 and 25, between whichthe outer wall of the base part 13 extends in a circular arc shape. Thecover part 15 has the same external circumference shape as the base part13 and, like said base part, it has opposite flattenings 27 and 29,between which the external circumference likewise extends in a circulararc shape. When the cover part 15 is mounted on the base part 13, astep-free outer contour of the damping housing is thus formed, as FIG. 3shows.

As is shown by FIG. 5 and also by FIGS. 8 and 9, the cover part 15 has aflange part 31 with fixing holes 33. These are arranged, as FIG. 9shows, on a partial circular arc outside of the region of theflattenings 27 and 29. In correspondence with the fixing holes 33,threaded bores are provided in the base part 13 as blind holes forfixing screws 35, by means of which the cover part 15 can be fixed tothe base part 13 in such a way that the flange part 31 of the cover part15 overlaps the circumferential edge 37 of the central recess 17 of thebase part 13. A circular engagement piece 39 extending downwards fromthe flange part 31 engages in a fitting manner into the central recess17 of the base part 13. This engagement is depicted in the screwed statein FIG. 5. For the purpose of sealing the cavity 7 relative to the coverpart 15, a sealing ring 43 is used in an annular groove 41 incorporatedinto the side wall of the engagement piece 39.

For the attachment of the damping housing to corresponding thirdcomponents, in the depicted exemplary embodiment, threaded bolts 45 areprovided on the flattening 25 of the base part 13 comprising the fluidoutlet 5, which threaded bolts are arranged symmetrical to the fluidoutlet 5. In addition, a receiving groove 47 for a sealing ring isformed on the opposite flattening 23 at the fluid inlet 3. Fixing bores49 are also arranged on this flattening 23 for the formation of couplingconnections, which fixing bores are in a symmetrical arrangementrelative to the fluid inlet 3. It shall be understood that, in acorresponding manner, a sealing arrangement can be provided on theflattening 25 assigned to the fluid outlet 5. The symmetrical housingconstruction also allows the interchanging of the inlet side and theoutlet side, potentially with changed sealing geometries.

To the extent described above, the exemplary embodiment of the dampingdevice corresponds to the disk silencer as is disclosed as subsequentlypublished prior art in the above-mentioned patent application DE 10 2014005 822.0. The essential difference of the present invention comparedthereto is that a flow guide element 51 is arranged in the disk-shapedcavity 7 forming the fluid receiving chamber. As can be most clearlyseen from FIGS. 2, 9 and 11, said flow guide element has a wedge shapesuch that, starting from a narrow onflow region 53 forming a kind ofwedge tip, guide surfaces 55 are formed, which diverge in thethroughflow direction indicated with the arrow 57. The guide element 51thus forms a kind of flow divider for a flow course, as indicated inFIG. 2 in a schematically simplified manner, with side zones 59, inwhich the flow is partially accelerated, and zones 61 and 63 withcomparatively lesser flow speed.

The guide element 51 is formed integral with the cover part 15 as aprojection, which protrudes from the boundary wall 21 on the engagementpiece 39. The height of the projection corresponds to the disk thicknessof the disk-shaped cavity 7, so that the guide element 51 extends fromthe boundary wall 21 of the cover part 15 in a continuous manner up tothe boundary wall 19 on the base part 13. The guide element 51 iscentrally arranged in the cavity 7, so that the pointed onflow region 53is situated on the housing axis 11 which extends from the fluid inlet 3to the fluid outlet 5 approximately at half the length thereof betweenthe inlet 3 and the outlet 5. Instead of the wedge shape shown in thepresent example, a different shape can be provided for the guide element51, with which the guide surfaces produce a flow profile which issuitable for high-efficiency damping in the disk-shaped cavity 7 withouthaving an adverse effect on the flow resistance.

It shall be understood that, instead of the depicted integral formationof the guide element 51 as a projection on the boundary wall 21 of thecover part 15, a separate installation part can be provided as the guideelement. Furthermore, more than one guide element could be provided,which could potentially have different shapes and sizes. The depictedpositioning of the guide element 51 on the housing axis 11 is also notmandatory.

1. A damping device, in particular for damping or avoiding pressuresurges, such as pulsations, in hydraulic supply circuits, preferably inthe form of a silencer, having a damping housing which surrounds adamping chamber and has at least one fluid inlet (3) and at least onefluid outlet (5) and a fluid receiving chamber (7) which extends betweenthe fluid inlet and the fluid outlet, wherein, during operation of thedevice, a fluid flow crosses the damping chamber in a throughflowdirection (11), coming from the fluid inlet (3) in the direction of thefluid outlet (5), and wherein at least parts of the fluid receivingchamber (7) extend in at least one extension direction transversely withrespect to the throughflow direction (11), characterized in that thefluid receiving chamber (7) immediately adjoins the fluid inlet (3) andthe fluid outlet (5) and in that a guide element (51) is provided in thedamping chamber, onto which guide element the fluid flow can flow andwhich changes the flow speed of the flow in regions.
 2. The dampingdevice according to claim 1, characterized in that the fluid receivingchamber is formed by a cavity (7) in the form of a disk with twoboundary walls (19, 21) which extend parallel to one another anddetermine the thickness of the disk, and in that the guide element (51)extends in a continuous manner from one boundary wall (21) to the otherboundary wall (19).
 3. The damping device according to claim 1,characterized in that the disk-like cavity (7) is formed cylindrical oras a polygon.
 4. The damping device according to claim 1, characterizedin that parts of the fluid inlet (3) and of the fluid outlet (5) extendin alignment with the boundary walls (19, 21) in the damping housing. 5.The damping device according to claim 1, characterized in that the guideelement (51) is arranged in a position aligned with the housing axis(11) extending from the fluid inlet (3) to the fluid outlet (5).
 6. Thedamping device according to claim 1, characterized in that the guideelement (51) is arranged at least approximately in the region of half ofthe length of the housing axis (11) extending from the fluid inlet (3)to the fluid outlet (5).
 7. The damping device according to claim 1,characterized in that the guide element (51) is formed as a flow dividerwith guide surfaces (55) which extend to both sides from a narrow onflowregion (53) which faces the fluid inlet (3) and which is located on thehousing axis (11).
 8. The damping device according to claim 1,characterized in that the fluid inlet (3) and fluid outlet (5) formed asdamping housing bores have an identical diameter and said diametercorresponds to the spacing between the two boundary walls (19, 21). 9.The damping device according to claim 1, characterized in that thedamping housing is formed in several pieces, with a pot-like base part(13), which receives a disk-like central recess (19) forming part of thecavity (7) with the one boundary wall (19) and also the fluid inlet (3)and the fluid outlet (5), and with a flange-like cover part (15) which,with the other boundary wall (21) as part of an engagement piece (39),engages in a flush manner in the central recess (17) when the cover part(15) is fixed to the base part (13).
 10. The damping device according toclaim 1, characterized in that the guide element (51) is formed integralwith the cover part (15) and projects from the boundary wall (21) formedon the engagement piece (39).
 11. The damping device according to claim1, characterized in that a sealing device is arranged on the engagementpiece (39) of the cover part (15), which sealing device is in particularin the form of a sealing ring (43) inserted in a circumferential groove(41), which seals the cavity (7) as a component of the central recess(17) relative to the environment.
 12. The damping device according toclaim 1, characterized in that the cover part (15) has, lying oppositediametrical to its vertical axis, several penetration bores (33) which,penetrated by fixing screws (35), fix the cover part (15) to the basepart (13).
 13. The damping device according to claim 1, characterized inthat the fixing screws (35), while leaving the region of the fluid inlet(3) and the fluid outlet (5) free, are arranged uniformly along anexternal circumference on the damping housing, which surrounds thedisk-like fluid receiving chamber (7).
 14. The damping device accordingto claim 1, characterized in that a receptacle (47) for a sealing ringis provided at the fluid inlet (3) and/or at the fluid outlet (5) in thedamping housing, which sealing ring surrounds the fluid inlet (3) and/orthe fluid outlet (5).
 15. The damping device according to claim 1,characterized in that, in the manner of a fixing block, the dampinghousing can be fixed to third components by means of several fixingbolts (45), which surround the region of the fluid inlet (3) and/or ofthe fluid outlet (5).